Pooja, many of us have this same type of lump in our throat. I know I did for many many years. There is little evidence that diabetes causes depression, but much evidence that diabetics have a greater incidence of depression. IT makes sense, We are dealing with a chronic disease without immediate cure and which requires constant management. It is daunting.
I felt this lump in my throat until I came to understand I was depressed. It was important for me to work to get that cleared up. So today I use antidepressants, and talk therapy to gain insight and help me. Not knowing any of the situation in your life, I wonder if this might be helpful for your issues.